Too little UV light?
 

I read an article in the 2007 annual of Marine Fish and Reef stating modern reefkeepers have successfully duplicated the colors and intensity of natural light, but we have failed to duplicate UV.

Since UV light naturally penetrates the first 10 feet of the ocean where the most colorful corals are found, why do we not apply the same technology in our tanks (99% of which are shallower than 10 feet in depth)?

I know hqi bulbs have to be covered because of their strength, but we should be able to use a medium wattage uv (e.g. tanning) bulb without harm. Has anyone researched this and found the appropriate watts/gal UV?

[QUOTE]Since UV light naturally penetrates the first 10 feet of the ocean where the most colorful corals are found[/QUOTE]

I've heard the opposite actually; most of the more colorful corals tend to come from deeper than 10 feet.

UV can certainly harm...or kill, but most research seems to be based on UV-B exposure. More harmful UV-B rays (wavelength 315-280 nm) are strongest during the midday hours, but less harmful UV-A rays (400-315 nm) are equal in intensity throughout the entire day of sunlight exposure.

UV-A has a greater penetration power in water than UV-B or visible light, and there is even evidence that UV-A may actually help to photorepair the damage caused by UV-B radiation.

That's about the depth of my UV knowledge, so I'll defer to wiser men or even wiser women.

Any input would be schweet.

There are a few corals that benefit from UV-A... FEW. I talked about this at length with Dana Riddle in the past, and the thing is, UV-A even is so easy to overload a coral (photoinhibit) with that its just not worth it. That, and it turns out that the UV output of most halide bulbs (SE or DE w/ sheild) is beyond what natural conditions provide, AND we arent keeping our corals in as much water depth... so if anything, we should be concerned about making too much UV it seems.

makes sense
 

I haven't seen any studies done in the non-visible output of haides, so I'll defer to you.